Blend Your Own Seed-Starting Mix

How to make your own seed-starting mix.

        4 parts screened compost (look below)

        1 part perlite

        1 part vermiculite

 

      2 parts sphagnum peat moss and/or coir

To keep the dust down, lightly moisten the ingredients before blending them thoroughly in a dishpan or wheelbarrow.

This mix strikes a balance between moisture retention and drainage, both of which are necessary for seedlings. Regulating the moisture is key, “It’s easy for the soil to stay too wet, and that can lead to damping-off.” Damping-off is a fungal disease that causes newly germinated seedlings to topple over and die. Some flower seedlings, tend to be more sensitive to too much moisture. For those, she makes a special batch of the mix, using less compost and replacing coir with peat moss. Sphagnum peat moss and perlite tend to lighten the mix and allow it to drain more quickly. Compost, vermiculite, and coir increase moisture retention.

This mix is made mostly from shredded leaves and other garden debris—but she avoids any organic materials that might introduce weed seeds to the compost. Having compost in the mix means that seedlings rarely need to be fertilized until they are moved outdoors to the garden; the compost provides a constant mild feeding. Compost also counters the natural acidity of peat moss. In mixes that don’t include compost, add 1/4 teaspoon of lime for every gallon of mix.

Build a Compost Screener

Prevent rocks and plastic from getting into your compost by creating a compost screener.

 

If you have a screen for cement you may use it or you can make your own.

Some organic debris breaks down quickly into compost, while twigs and hedge trimmings lag behind. This compost screener allows gardeners to remove the chunky, unfinished bits from compost that is to be used in potting mixes or as a soil amendment or topdressing. It also removes stones and plastic trash that may have found their way into the compost pile. Use a gloved hand to work the compost through the mesh, one or two shovelfuls at a time.

The screener is designed to sit atop a wheelbarrow or garden cart; the screened compost ends up in the wheelbarrow so it can be transported to wherever it is needed. Materials needed are 2-by-4 untreated framing lumber, galvanized hardware cloth with 1/2-inch square mesh, 2 1/2-inch galvanized deck screws, and 3/4-inch galvanized staples.

Begin by measuring the wheelbarrow. The dimensions of the wheelbarrow tray will determine the lengths of the 2-by-4s. Cut two boards about 16 inches longer than the width of the top edges of the tray, allowing them to overhang the edges 8 inches on each side. Cut two shorter boards about 8 inches less than the cross dimension. (The screener can be built so the overhanging boards extend to the sides of the wheelbarrow, or to the front and back. A rectangular shape is easiest to construct, although it’s also possible to match the tapered shape of some wheelbarrow trays.)

With a handsaw or jigsaw, cut long notches at each end of the longer boards. The cuts can be angled or curved with a jigsaw, if desired, to make the screener fit more snugly atop the wheelbarrow. Check to make sure the notched boards fit the wheelbarrow tray. Assemble the four boards with 2 1/2-inch deck screws.

Cut a rectangle of hardware cloth to fit the underside of the screener. Attach it with a staple gun, fastening about every 6 inches.

Using Screened Compost
Three good uses for screened compost:

Lawn fertilizer. Spread about 1/4 inch of screened compost on the lawn in early fall. Use a leaf rake to distribute it evenly.

Mulch. Blanket the soil in planting beds with an inch or more of screened compost. As mulch compost offers slow-release nutrients and a tidy appearance.

Potting soil. Fortify houseplant or seed-starting mixes with compost, adding one part of screened compost for every three parts of commercial potting soil.